Compliance of left atrium with and without left atrium appendage

Abstract

Compliance of the left atrial chamber was estimated with and without the appendage intact in six isolated canine left atria. Pressure-volume determinations were measured over a range of 5-30 mmHg for the whole left atrium and were repeated with the appendage excluded. The slope of the pressure vs. normalized volume data for the left atrium without the appendage (10.45 +/- 0.87) was significantly greater (P less than 0.01) than with the appendage intact (4.10 +/- 0.72). These data suggest that the left atrial appendage is more compliant than the remaining left atrium. Assuming that this relationship remains in vivo, the left atrial appendage may play an augmented role in maintaining hemodynamic function when filling pressures are elevated.

Regional left atrial interstitial remodeling in patients with chronic atrial fibrillation undergoing mitral-valve surgery

“…Differences in regional distensibility and function exist between the left atrial body and the LAA. The LAA appears more compliant than the remaining left atrium, and it may play a crucial role in maintaining hemodynamic function when filling pressures are elevated [10,13]. Extracellular matrix remodeling of the left atrium in patients with hemodynamically overloaded and with dilated atria, favors the occurrence and the perpetuation of AF as well as the reduction of left atrial compliance.…”

Morphology of the left atrial appendage

“…This study cannot answer the question whether these differences are the consequence of haemodynamic changes connected with atrial fibrillation. It has been shown in animal studies that the myocardium of the left atrial appendage is more compliant than the myocardium of the left atrium (Davis, 1990). It has been postulated that the appendage modulates the relation between pressure and volume in the left atrium (Hoit, 1993).…”

ELAT Study (Embolism in Left Atrial Thrombi): Baseline Clinical and Echocardiographic Data

“…Our find ings support observations from animal models about the function of the LAA. In vitro, the LAA has been shown to be more compliant than the remaining left atrium [19]. This relationship remains in vivo, and the LAA plays an important role in maintaining hemodynamic function when filling pressures are elevated [20], In our study, LAA size was increased in patients with valvular abnormalities (thus leading presumably to elevated filling pressures), whereas LAA size was associated neither with increased left atrial diameter nor heart failure (table 2).…”